Undefined name: import boto3 for lines 49 and 54

[cclauss]

flake8 testing of https://github.com/SeldonIO/seldon-core on Python 3.8.0

$ flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics

./examples/models/openvino_imagenet_ensemble/resources/model/Prediction.py:48:17: F821 undefined name 'boto3'
    s3_client = boto3.client('s3', endpoint_url=s3_endpoint)
                ^
./examples/models/openvino_imagenet_ensemble/resources/model/Prediction.py:53:19: F821 undefined name 'boto3'
    s3_transfer = boto3.s3.transfer.S3Transfer(s3_client)
                  ^
./examples/models/templates/ModelName.py:1:6: E999 SyntaxError: invalid syntax
from <your_loading_library> import <your_loading_function>
     ^
./util/loadtester/scripts/mnist_grpc_locust.py:148:32: F821 undefined name 'r'
                j = json.loads(r.content)
                               ^
1     E999 SyntaxError: invalid syntax
3     F821 undefined name 'boto3'
4

https://flake8.pycqa.org/en/latest/user/error-codes.html

On the flake8 test selection, this PR does not focus on "style violations" (the majority of flake8 error codes that psf/black can autocorrect). Instead these tests are focus on runtime safety and correctness:

• E9 tests are about Python syntax errors usually raised because flake8 can not build an Abstract Syntax Tree (AST). Often these issues are a sign of unused code or code that has not been ported to Python 3. These would be compile-time errors in a compiled language but in a dynamic language like Python they result in the script halting/crashing on the user.
• F63 tests are usually about the confusion between identity and equality in Python. Use ==/!= to compare str, bytes, and int literals is the classic case. These are areas where a == b is True but a is b is False (or vice versa). Python >= 3.8 will raise SyntaxWarnings on these instances.
• F7 tests logic errors and syntax errors in type hints
• F82 tests are almost always undefined names which are usually a sign of a typo, missing imports, or code that has not been ported to Python 3. These also would be compile-time errors in a compiled language but in Python a NameError is raised which will halt/crash the script on the user.

[seldondev]

Hi @cclauss. Thanks for your PR.

I'm waiting for a SeldonIO member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[axsaucedo]

boto3 is used in the code, so it may be due to installed dependencies (have a look at the rest of the file)

[axsaucedo]

/hold

[cclauss]

Some other Python file may be importing boto3 so it is already in memory. If that is the case then this PR is a safety measure because if that other file is changed to not not run first or import boto3 then this file would fail at runtime. Explicit is better than implicit.

[adriangonz]

/hold cancel
/ok-to-test
/approve

You are right @cclauss, it makes sense to add the boto3 import. I imagine that right now is not crashing because it's taking a different code path.

[seldondev]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adriangonz

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• OWNERS [adriangonz]

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[seldondev]

Mon Feb 17 10:51:35 UTC 2020
The logs for [pr-build] [1] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1441/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1441 --build=1

[seldondev]

Mon Feb 17 10:51:40 UTC 2020
The logs for [lint] [2] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1441/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1441 --build=2

[seldondev]

Mon Feb 17 11:02:02 UTC 2020
The logs for [pr-build] [3] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1441/3.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1441 --build=3

[seldondev]

Mon Feb 17 11:02:11 UTC 2020
The logs for [lint] [4] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1441/4.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1441 --build=4